cetacean, cetacean mammal, blower - large aquatic carnivorous mammal with fin-like forelimbs no hind limbs, including: whales; dolphins; porpoises; narwhals

spiracle - a breathing orifice

air duct, air passage, airway - a duct that provides ventilation (as in mines)

hole - an opening deliberately made in or through something

smoke hole - a vent (as in a roof) for smoke to escape